1. Field of the Invention
The present invention relates generally to chemical analysis, and more particularly to a cuvette for use in colorimetric analysis, a cuvette magazine containing a number of cuvettes therein and a cuvette auto-loading apparatus for supplying the cuvettes into a reaction line of an automatic analyzer in succession.
2. Description of the Prior Art
There have been proposed various types of automatic chemical analyzers. In a colorimetric analyzer, a sample such as a serum and a reagent are delivered into a reaction vessel fed along a reaction line to form a test liquid and then the light absorption of the test liquid is photometered to effect a quantitative analysis. Such analyzers may be classified into direct measuring systems in which the test liquid contained in the reaction vessel is photometered and indirect measuring systems in which the test liquid is transferred from the reaction vessel into a flowcell and the test liquid in the flowcell is photometered. From the view-point of construction of the analyzer, the former system is superior to the latter system, because the construction can be made much simpler in the former system. As to the treatment of the reaction vessel, there are two systems. In the first system the reaction vessels travelling along the reaction line are used repeatedly, while in the second system new reaction vessels are fed successively into the reaction line. In the first system a mechanism must be provided for washing and drying the reaction vessels, so that the whole apparatus is liable to be complicated in construction, large in size and expensive. Further, the first system requires a great amount of a washing liquid and a problem occurs in treatment of waste washing liquid. If the washing is not effected sufficiently, contamination may occur between successive test liquids, which affects the accuracy of measurement. Moreover, while the reaction vessels are used repeatedly, they are liable to be injured or scratched and therefore the measuring accuracy might be decreased. Contrary to this, in the second system the above problems can be entirely removed, because the reaction vessels which have been once used are discharged. However, an automatic vessel loader must be arranged for supplying new reaction vessels into the reaction line. Known automatic reaction vessel loaders have several drawbacks including that they are of complicated construction and require very cumbersome treatment. Particularly, when the reaction vessels are held by hands, finger-prints might be applied on the reaction vessels. Further, the known, auto-loaders do not work positively and reliably and often fail to feed the reaction vessels in the reaction line in a correct order.
As explained above, in the known chemical analysis, in order to effect a precise analysis the reaction vessels must be handled very carefully not to be stained or injured. In the known analyzer of the direct measuring type use is made of reaction vessels comprising a test tube or a box-shaped cuvette. In these test tubes and cuvettes, the entrance and exit windows for a measuring light beam are directly exposed to the outside and thus are liable to be stained and injured. Further, disturbing stray lights are liable to impinge upon the cuvette to decrease the measuring accuracy.
Moreover, in the known auto-loaderd, it is quite cumbersome to charge or set the reaction vessels or cuvettes into the auto-loader. This operation requires a long time and the analysis has to be interrupted during the charging operation.